1 tn BDAG 825 s.v. πλῆθος 2.b.γ has this translation for πλῆθος (plhqo").
2 tn These clauses are a good example of the contrastive μὲν…δέ (men…de) construction: Some “on the one hand” sided with the Jews, but some “on the other hand” sided with the apostles.